To be completely honest, if this was linked to me at the time I knew nothing about using Construction Set, I'd probably go insane.
8bit bob, my warm suggestion is not to start with an actual mod right off the bat. Open the Construction Set, and click on random things, see what does what. Very basic things to start with:
when you open CS nothing will be loaded. You have to go to File, Data Files, and mark Morrowind (and Tribunal and Solstheim if you want to, you'll get loads of error messages, but that's normal, just hit y and hold it until it continues to load). Set up the the windows as you like it (I personally like having object window on the left, narrow, from top to bottom, and cell rendering taking the rest of the screen from there, with cell view window hidden behind it, so you can just click on top of it when you need to change a cell).
Click on some cell from the cell view, like Seyda Neen, and move things around, double click of them to see what items have what parameters for change, etc. Try shortcuts, for movements, they are actually very obvious, moving things while holding y,x, and z will move an object on those coordinates, holding s will scale an object, etc. F puts an object on the "floor" (actually, on the first surface beneath the objects, but you can press it several times to sink it in, and fall on surfaces bellow). Using the render window, and knowing how to make new objects and change their basic parameters is basics of the basics, and I don't recommend getting deep into other topics until you cover these basics.
Important tips are: 1. there are no "references" like in later games. If you don't know what that means, in short, don't change parameters, such as damage, on a dagger you opened from the field, unless you want to change damage for all of those daggers in the game. If you want to create a new weapon with your own parameters without changing all the other copies, delete the ID and write something of your own there, and place it in the world/change the existing one (it'll ask you to create a new object, say yes). Most modders use initials or some short form, so if you plan to release mods make one of your own, something short. For example, I use CH, Melchior uses MD, so you could use something like 8B (this one's actually great, as not a lot of IDs start with a number, so your custom objects will mostly appear on top of the lists). This used to be a must because many people used generic IDs, and then there were conflicts if someone wanted to use two mods that had objects with the same ID, and you can't have the same two IDs in the game at once.
2. when you save your work and wish to continue another time, the next time you open up the CS you don't have to mark the mods your mod is dependent on (whatever you marked when you started making your mod, Morrowind + extras), but just marking your own mod is not enough. You have to highlight it and press "set as active" to actually continue working on the mod. Otherwise you'll make ANOTHER plugin file that's dependent on your previously saved plugin file.
3. when you move objects in the world from their editor window (as in, you double clicked on an object and are using x/y/z numbers to change position/rotation of an object), never use "save" to save the changes, use cancel instead. Otherwise you're creating dirty edits that create instabilities in your mod, and you don't want that. When you get a bit more savvy you'll learn to utilize 3rd party programs that can clean these dirty GMSTs, which like to somehow pop in even if you're experienced modder. This is a bit early to teach you that since you won't be releasing a mod in the next couple of days (or maybe you will ), but it's a good thing to get used to use cancel rather than save, right away. I learned this after I was already a few years into modding, and it was really hard for me to get rid of the habit to save my way out of the window.
Even this is too much to read without actually looking at the CS, but you'll have more questions as you go on, click on things, and start wondering what does what. When you get into modding a bit deeper, go back to the link above, but currently there's tons of info just in preparations section that you absolutely don't need to know right now in order to start learning how to use the CS, and most of it will mean nothing to you.