Hi jataysmimi,
Welcome to the Apple Support Communities!
I understand you have some questions about clearing out photos from your iPhone and laptop. I'm glad you asked the question before deleting your photos from your iPhone. I am not familiar with the Photo Stick product so I can't really comment on that. I can however, provide you with some general guidance along with a few questions. Based on your response to this thread, I will be able to guide you further.
Do you have iCloud Photos enabled on your iPhone?
What is the capacity of your iPhone and how much free space do you have remaining?
Do you have a Mac or a Windows computer?
What is the capacity and how much free space do you have remaining?
Generally speaking, if you have iCloud Photos enabled, you can choose the Optimize feature which keeps the high resolution images in iCloud, while showing smaller versions on your devices which frees up space.
You should always have two backups of your data. If you have a Mac with Time Machine, that will be backing up the photos on your computer if you've synced or transferred them from your iPhone.
If you copy files to an external thumb drive or hard drive, make sure that you can open them before deleting them from your iPhone or computer. Also - how that external thumb drive is formatted depends on what computer and operating system you are using. If your pictures are in a library, you normally have to export them to an external drive.
Here are some general resources that may or may not apply to your situation. I look forward to hearing back from you with more pieces to this puzzle so that I can make sure your photo memories are protected.
Set up and use iCloud Photos
Archive or make copies of the information you store in iCloud
Transfer photos and videos from your iPhone, iPad, or iPod touch
Take care.