Network Extension with Airport Express

OK, thanks for clarifying that.

Temporarily, move the AirPort Express to the same room or close proximity to the Time Capsule

Power up the Express and let it run a a minute or two

Hold in the reset button on the Express for 7-8 seconds and release

Allow a full minute for the Express to restart to a slow, blinking amber light status

On your Mac......

Click on the WiFi menu at the top of the screen

Look for a listing of New AirPort Base Station

Just below that listing, click directly to AirPort Express

When you click on AirPort Express, that will start up the AirPort Utility setup "wizard". The wizard will take a few seconds to analyze the network and then display a screen that is similar to the screen that you see below, except that you will see your devices and network name displayed

Next to Base Station Name.......Type in a short simple name for the AirPort Express

Click Next

The next screen that appears will confirm that the AirPort Express is being set up to wirelessly extend the Time Capsule network

When you see the message of Setup Complete, click Done.......and you are done.

Power off the AirPort Express and move it to a location that is approximately half-way between the Time Capsule and the general area where you need extended WiFi coverage.

Power up the AirPort Express and wait a minute for the green light.

The more that you can keep a line-of-sight relationship between the Time Capsule and the AirPort Express, the better the network will operate.

And what device........a Mac computer, a PC, or an iPhone / iPad will you be using to set it up? We ask because the set up is different for each one of these devices.

Hopefully, you are planning to connect the Express back to the Time Capsule using a permanent wired Ethernet cable connection, correct? We ask because you will reduce the overall network speed by half or more if you use wireless to connect the Express to the Time Capsule.

Finally, it would really help to know which model of AirPort Express that you have, since there are different models, some which cannot wirelessly extend the signal from the Time Capsule.

Sounds like the version of the AirPort Express that you have has two Ethernet ports.......like the example below. Is that correct?

Nice work!