Another consideration, and probably getting too technical for the OP here, is image b/u's vs. file-by-file b/u's. The former takes a "snapshot" of the whole disk and saves it to backup media, the latter saves individual files as represented on the source disk. Imaging is generally easier to set up, and recover from a crashed source disk, but you lose the ability to easily "roll-back" individual files (e.g. you make a change to a program's configuration file that causes unwanted behavior, with a file-based backup, you have the option of restoring only that file. With imaging, you send the entire computer back in time to when you took the snapshot. Another advantage to file-based is the ability to restrict the backup set to a smaller number of files, thereby speeding up the process and taking less space on the backup media. I think most professionals these days do both kinds of backups, imaging for disaster recovery and file-based for the occasional single file restore.

Let me throw my 2 cents in.

That 1 TB should be big enough. When you get it, plug the drive to a USB port on your computer. It will show up as a drive. I'm betting it will be drive D.

Use your file explorer to create a folder called "Documents yymmdd" But instead of yymmdd, enter the two digit year, two digit month, and two digit date. So if you're creating a back up on Jun 20, 2021 the folder name will be Documents 210620. Create another folder and name it Pictures yymmdd.

Open another instance of file explorer so you have two windows. On the first one, click in the documents yymmdd folder so you're "inside" it. On the second file explorer, go to your My documents folder. Then you're going to do the following:
1) Ctrl + a (click on Ctrl key and the a key together. This will select all the files in your my documents folder.)

2) Ctrl + c (This will make a copy of the files in your my document folder into memory.)

3) Click on the first file explorer window where you're in the documents yymmdd folder in the USB drive.

4) Ctrl + v (This will paste a copy of the files from your computer's my documents folder to the USB drive's document yymmdd folder that you just created.

5) Repeat steps 1 - 4 above for the files in the Pictures folder.

When you're done, unplug the USB drive from your computer. Next month, create two new folders again for Documents yymmdd and Pictures yymmdd.

When the USB drive is full and it says not enough space, just delete the oldest folders.

This gives you the simplest method of keeping backup copies of your files. You unplug the USB drive after each time so that in case your computer gets infected with malware that locks your data, the data in the USB drive won't be affected.