What you need

Steps

For a new aircraft, tap + in Hangar, then tap Read manual (PDF). For one you have, open it and tap Read the manual.
Choose the PDF in Files, or paste a link to it. You can also share a PDF to Maiden from Files or Mail.
Wait while Maiden reads each page. Pages that are pictures take a moment each.
Check each value. Tap its page number to see where it was read.
Turn on the CG and the throws you want, after checking them against the page.
Tap Use, then Save if you're adding a new aircraft.

Details already on the aircraft stay unless you turn their switch on.
The manual's CG shows beside the CG calculator and the balance level.
The manual's throws show as targets in the throw meter. Your own measurements stay as they are.
Only English text is read. Most manuals have an English section.

Nothing was found: Some manuals print their tables in a way that can't be read. Scan the spec page with Scan box instead.
The wingspan wasn't found: Some manuals only draw it. Pick it from the sizes beside the drawing, or measure it.
A link didn't work: Copy the link to the PDF itself, not to the shop's page. Or download it and choose it in Files.

CG: Center of gravity: the point where the model balances. Too far back makes it unstable. Too far forward makes the nose hard to lift.
Throw: How far a control surface moves from center, in degrees or as travel at its trailing edge.
Rates: Throw settings you switch between on the transmitter. Low rates are gentler for normal flying, and high rates are for aerobatics.