how do i upgrade a MacBook pro 2011 without using the internet

Since you have an old Mac running High Sierra, I strongly encourage you to create a "bootable installer" of that operating system: Create a bootable installer - Apple Support

You can certainly copy the installer app as Niel wrote but the "bootable USB installer" will be the only way to install High Sierra in the event you ever misplace that app. The reason is that Apple quietly removed the ability to reinstall High Sierra (and presumably, earlier versions) from their Recovery servers a while ago. Without the Install OS X High Sierra app or a "bootable USB installer" you will be left with very few alternatives, all of them bad.

The following is the procedure I use and illustrates what you should see when creating a "bootable installer". Perhaps you will notice something different than what you have been experiencing.

To create a standalone installer on a USB flash drive or similar removable media, refer to the following instructions: Create a bootable installer for macOS - Apple Support.

Expanded instructions are as follows:

• Format the USB installer as Mac OS Extended (Journaled) and GUID Partition Map.
• Make sure its icon is present on your Desktop. Its name isn't important because createinstallmedia will change it.
• Also, the Install macOS High Sierra app must be present in your Mac's Applications folder, otherwise the pathname shown below won't be correct.
• Make the Finder's Applications window small enough so that you can see it, the Terminal window, and the USB drive icon, all at the same time.

Select the following line by dragging your cursor from just prior to the word sudo to just past the word volume. Don't triple-click the entire line and don't drag your cursor below the line:

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume 

Confirm that nothing is highlighted other than that line. Nothing before sudo and nothing after volume.

Then, Edit > Copy.

Go to the Terminal window, paste that line into the Terminal window, and type a space character. Stop right there; do not press Return.

Drag the SD card or USB flash drive icon from your Desktop to the Terminal window, and stop again.

Then, type (or copy/paste) the following into Terminal:

--applicationpath 

... followed by another space character.

Then, drag the Install macOS High Sierra icon from your Applications folder into the Terminal window.

Finally, you can press Return.

This is an example of what should happen. The name of the USB drive is "untitled" in the following:

MacBookAir7:/ john$ sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/untitled --applicationpath /Applications/Install\ macOS\ High\ Sierra.app 
Password: (type your Admin password - it will not be echoed, not even with •••• characters. Then press Return)
Ready to start.
To continue we need to erase the disk at /Volumes/untitled.
If you wish to continue type (Y) then press return: Y
Erasing Disk: 0%... 10%... 20%... 30%...100%...
Copying installer files to disk...
Copy complete.
Making disk bootable...
Copying boot files...
Copy complete.
Done.
MacBookAir7:/john$

When it's finished the name of your USB or SD card installer will be Install macOS High Sierra and it will be selectable as a bootable device in Startup Manager: How to choose a startup disk on your Mac - Apple Support.

Yes. Drag the downloaded dmg or installer application to it, or clone the High Sierra system to it.

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No, many are not formatted in a format compatible with the Mac.

In your case , you’ll need to format it using the “Mac OS Extended (Journaled)” format (which is required for the bootable key). This document will tell you how: Erase a volume using Disk Utility on Mac - Apple Support.

No, but Create a bootable installer - Apple Support describes what you need to do. When you insert the USB flash drive, the Mac might say "the device you inserted is not readable by this Mac" or words to that effect, with an option to "initialize" it. That's what you will be doing.

Maybe. I'm not at a Mac right now but for the time being be sure you follow the instructions in Create a bootable installer - Apple Support to the letter. For example, there are names given such as MyVolume that are mere placeholders and are meant to be replaced with the actual names you provided. And, you have to be sure to precede any space characters with a backslash to indicate the next character (the space) is to be included and doesn't indicate the completion of what you entered up to that point.

All this might make it appear more complicated than it is. Somewhere on this site I posted explicit step-by-step instructions that illustrate how to do it in a simple manner, but it'll be a little while before I can find them and post them here. I'll do that when I'm able.

Apparently this is going to be more difficult than I had imagined. The "unable to verify" might be due to a certificate that has expired. The solution would be to temporarily change the Mac's system date to one in the distant past, say perhaps five years ago. But without knowing exactly what the message says, and lacking a Mac that can actually run Lion, I can only speculate.

If you want to pursue that possibility, the workaround would be to use the Utilities menu option in macOS Utilities, and choose Terminal. To change the Mac's date in Terminal to March 17, 2015 at 5 PM the Terminal command would be

date 031717002015

... but I have no idea whether that will work, or will solve the apparent inability to verify the High Sierra installer app. You can try it though.