The Analysis Engine List is a DialogBox where SCID keeps track of all the engines you have used, along with an estimated Elo rating (which you can find on dedicated sites) and the date when each engine was last used.
Yes!
Click on "name", "Elo" or "date" to sort by alphabetical order, strength, or date (last used first).
Of course!
Select the Edit button to edit the details for an existing entry, or the Delete button to delete an engine from the list.
Here are some instructions to get you started with chess engines.
Make sure you have a new engine to install.
Consult [GetResources] for a list.
Go in Tools/Analysis Engine or press CTRL-Shift-A or click on the Train icon
The engines you already have installed should be listed there. Since you want a new one, click on New. A new dialog box should appear: it looks like the one illustrated below.
Under Name, give it the name of your fancy (e.g. "Stockfish").
(The crucial step) At the right of "Command", you should see a box with an ellipsis (i.e. three dots, like this: "...") -- click on it.
In the Explorer window, go select your binary (i.e. a file which ends with .exe); when it's done, you should see a path to it in your Command box.
Make sure there's a dot for your Directory, then press OK.
Note. There's no need to modify anything else. If you want, consult the engine documentation.