How you layout your pattern pieces depends on how much fabric you have and the shape and size of your pattern.
A core or oblong pad shape will be easy to layout, and doesn’t waste much fabric at all. You can cut the core pieces with a square edge, but I find rounding them makes a neater and less pokey finish, as the corners of a rectangle core piece can curl up.
A contoured shape with a flared end can be “top and tailed” (where the pieces alternate to have the wider end with the narrower end) to use up a little less fabric. The top part of the image shows the top & tailed ones, the bottom shows how they would be if laid out all the right way up. It doesn’t save much (about half a core for every 4 cores), but every bit helps.
Standard winged pads should fit together well (Left). Patterns with a flared end will generally slot well into each other if you put some pieces upside down to make them fit – if the print allows that (Right)
Pocket pads need 2 back sections, which are each wider than half a pad, but they can be laid out efficiently too.
How much fabric you will need will depend on how many pads you want to make from it, and also the pattern you are using. You can work that out by measuring the width and length of your patterns, and estimating how many you’ll be able to cut out from your fabric. Always allow extra for shrinkage and the fact you’ll probably lose some to fraying in the wash – and it’s really frustrating if you can’t get a pad in because your fabric is *just* that little bit too small for what you need.