Safety first! So wear your knee pads! Next off, clean the floor thoroughly. Wash it if necessary, but make sure the floor dries properly before you start the flooring project. Also make sure there are no protruding objects on the floor, like nails. Remove them if you find any as this will easily show through the vinyl sheets. Also make sure you level uneven floors with proper guidance from a professional.
Now measure your floor area. As mentioned earlier, length by width. Leave a 75 mm gap on your vinyl (this is leaving room for error). Before you lay your vinyl, leave it on the floor to be fitted for 24 hours. This is to account for any changes that atmospheric moisture might bring on the sheet. Next you need to work around obstacles in the room, by cutting the vinyl around such obstacles. While some vinyls require only a perimeter bonding to the floor, some require you to spread adhesive all over the surface, like with wall-coverings. If the vinyl requires only perimeter bonding, use a double-sided tape. Finally, run corners with a sealant.
And with that, you are done!