Okay, I'll see if I can help.
Of course take the air cleaner off.
Disconnect the coil wire.
Then take the distributor cap off. Lay a straight edge down the center of the rotor and place a mark on the firewall. Now remove the single distributor hold-down bolt. Lift the distributor straight up/out little by little and notice that the rotor will turn as the distributor comes out. When it stops rotating but is still in the engine place the straight edge down the center of the rotor again and make another mark in the firewall. This is your reference point on where the rotor will be when you first start going back together and where it will be when fully installed.
Take the distributor all the way out, place a piece of masking tape over the rotor down to the distributor body on both sides - this is so it doesn't accidently get rotated while waiting to get re-installed.
Remove the linkage to the carburetor, and there will be other things like vacuum lines, a coil bracket, etc.
Remove the intake bolts - I think there are 12 or 16 of these? lift off the intake.
Now clean the old gasket material off the engine. I run a shop vac all around the gasket scraped area to get any little pieces lifted out of the engine.
Purchase an intake gasket kit.
I do NOT use the little end gaskets that come with the intake gasket kit.
At this point place the two main gaskets down each side of the engine and do a quick fit of the new intake manifold to see how things line up and "feel" as you lower is straight down into position. You can practice this for feel and position that works best. I would install the intake without the carburetor on.
Now remove the new intake manifold.
Now take silicone gasket sealer and run a nice bead down the ends where the little end gaskets that you are not going to use would go. Make sure the bead runs over and on to the little tab of the fiber gaskets going down each side.
I usually use two long bolts in the intake mainfold, one on opposite corners, to help me line up the intake as I carefully lower it into position. You will see when you did your trial fit above you are going down to a sloped valley surface and are balancing keeping gaskets in position and lowering it straight down to squash, not smear the silicone on each end.
Install all of the intake bolts by hand, then remove the long ones you use to assist you allignment and replace them with the correct ones.
Tighten the intake bolts after they are all installed, start in the center and move out. Starting at opposite courners I torque the bolts to specs, I think it is 15 Foot pounds. The reason I do this is to get the feel of when the bolts are torqued to specs because I end up doing the center bolts by hand - can't get my torque wrench in there so do it by "feel".
Of course hook everything back up as it was before you started. Re-time the engine when all back together and it is running okay.
I think others will help here at this site, so study the responses until you understand all of the things and it should be pretty easy for you.
John