There is a lot more to it than what you think. First of all- strip the old top off and repair the rust.
Next, order a pre-made top that will fit the car. Preferably from ACME Headlining Co.

Glue, edge trim, centering, covering the car from over spray . . . It will be a great experience. Unfortunately the newest book I'm working on isn't published yet. There is a chapter on installing vinyl tops that covers every aspect of the installation.

@Fred Mattson
Is Landau foam necessary? I seen some people installing the vinyl over the painted area.
I believe this car did not come with any edge trim. It was just glued on the edges and cut window areas where tucked inside window seal.

I would need to know what specific car this is to answer the question properly.

@Fred Mattson

It's a 1970 Datsun 510 bluebird coupe the rear roof line is more slanted than your regular datsun 2 door 510s

Closed cell foam was used on higher end luxury cars. I would not recommend it for this model. Contact Vic at TopsOnLine - 1-888-803-8505 and see if a top is available.

Making the top yourself is possible. You can sew the seams, but the best solution is to have a sealed top made from Haartz Levant Vinyl. Definitely use Weldwood Landau Top & Trim High Heat Resistant Contact Cement. Call me if you need any other assistance.

If you get the automotive upholstery handbook by Don Taylor there is a useful section on vinyl tops.Its also very good on other areas.He also has a book about custom auto interiors which I have found full of tips and ideas.

In Addition to the great advice from Fred Mattson, I would like to add the following;
As it appears from the photo you supplied, there is an existing landau top on the car. There are pluses and minuses regarding this. On the plus side, there will already be "trim" fastened at the edges and if in good shape, and carefully removed, may be reused after you install the new top.
Yes, use a quality heat-sealed replacement - and only sew if you're looking for a Euro-look with a convertible top material, like "Haartz" .
On the minus side, as you remove the existing top, "there will be some rust in some very critical areas" - like where the top tucks in under the window trim. Use the correct Trim-Bracket-Release-Tool which is available from most body-shop supply houses and carefully remove the windshield trim. You do not want to kink this and if you're having trouble, then please, enlist the services of a quality automotive glass technician . . . it will be a lot cheaper than trying to replace the existing trim molding !
Preparation: This is critical for the replacement top to look original. Aside from the rust you find around the windows, which should professionally repaired, there will be a lot of residual contact adhesive on the roof and sail panels. You have to completely remove this - all of it - otherwise the final result will be lumpy! Depending on the condition of the glue; If dried out, a few passes with a DA sander works well, if the glue is not dry, then the DA will just gum everything up - in these cases, I use a chemical solvent, like "Afta".
Ready to Install -
Dry-Fit the New Top - Fold the Top in half and cut a Center line V-Notch and then place some masking tape on both shields at the centers - Line up the V Notches and do some light trimming of excess materials - Sure - apply the contact adhesive Fred recommends - and be sure to do it evenly.
Let the glue dry to the point of your hands not sticking - This semi-dry condition will allow you to place the freshly glued top on the car and allow you to reposition it - so long as you do not press down firmly.
Line up your center lines - and then press down firmly on the top in the very center.
Now, you can work from the sides and pull out from the center and smooth out the vinyl - from the center out. When working the rear sail panels, you may need to use a heat-gun to soften the material, so you can then stretch the vinyl where the side sail panel meets the rear window area. Yes, a little experience helps here so as to not get wrinkles in the corners.
Take your time, if the glue gets too dry, you can reactivate it with the heat gun.