I've had mercy on you especially after the first line, I have a daughter with 2 grandchildren, 9 and 11 with a feckless husband.
Yes is the answer to your first question.
Don't use those diodes, you move the jumper fuse to neg application (see instructions) and conect the white wire to BROWN / blue at the hazard switch.
Remove the glove box. You will see a module in front of you with 1 black larger plug and two smaller plugs to the right. Middle plug either black or violet. These are called quadlock plugs. Take apart the middle plug. Unlock (blue/black) goes to pin 17 (blue/red) lock (GREEN/ black) goes to the vacant space in pin 4 opposite pin 17. Bare the end and "shove" in, then tape or cable tie to secure. Make sure no wire whiskers touch other pins. If there was a previous factory (dealer fit Gemini) in the vehicle cut the originals and solder and sleeve to yours.
A trick... take a diode 1N4004 etc from the GREEN/ black to the blue/black with the band towards blue /black. When finished set the alarm to total (or comfort) close. This will give you autolock on ignition (default) and dead lock and window (+roof if factory) close on arming.
BROWN / black and WHITE/ black ignore, purple and PURPLE / black via 5amp fuse to 12v+.
Look at loom going across the bulkhead from the driver's side. Light green is ign, (to the alarm's yellow) light/GREEN/ thin black is starter, if you decide to immobilise (and I don't advise it, cut the starter) and red is your power supply (12v+).
There are two mounting bolts to the left where the glove box fits with brown cables going to them. that's your ground (earthing) point, either one..
Doors bonnet (hood) and boot (trunk):- remember those two quadplugs? This time right hand. If four doors there will be four wires with brown as the primary with blue grey yellow etc as secondary, and yellow or silver dots. These are your door contacts. Check/test then join 1" length of green wire from alarm to each, then 1 x 1N4004 to each length with the bands away from alarm, then join all to the alarm's green. This is where your sleeving and solder comes in handy. If two doors, obviously you're only looking for two.
Trunk:- If 4 dr. saloon, passenger side rear, pull top of seat away, you might need something like a lever or pry bar, you will see a grommet at top of bulkhead. Coming out of this from the boot area and going up the "C" pillar is a BROWN / white wire. That's your trunk contact. If coupe, then go through the grommet into boot space (Tricky job without the right tools, white net curtain rod would be extremely useful on this job, about £3 from homebase) It's in the loom coming from passenger side rear light cluster, BROWN / white. You need to remove the inside lamp part (one twistlock) to pull lining carpet away. If it's a cabriolet, forget all the last it's up with the door switch contacts again BROWN / white behind glove box.
Bonnet, look to the driver's side striker plate. To the right of the rad are two holes. Measure off and drill 12mm (1/2") hole on the passenger side in the same position. That's for your bonnet switch (buy at Maplin along with your 3 or 5 diodes.) Also mount the siren on the near side forward on the wheel arch. Now go back to the glove box area, pull back the upper edge of the floor carpet and some foam above it. Right in the middle is your entry grommet. The curtain rod comes into its own here. N.B If your battery is in the rear you can get at this grommet from the engine bay firewall.
Ignore the purple wire that's joined to the green. Also if you have a blue wire that does bonnet and boot, place a diode (1N4004) on the boot's lead with the band away from the alarm. This will prevent a faulty bonnet switch turning on the boot light and flattening the battery. If there's a separate grey wire for the bonnet hood) ignore what I just said.
That's it.