I'm gonna guess that you mean vinyl, not linoleum, in which case Steve is basically correct, except that he also used the incorrect term lino to mean vinyl. You can lay the new floor over the old one, it is a common practice. Cut out any bubbles, raised or loose edges, damaged areas, then fill with a leveling filler, or as Steve said, fill in tile pieces for larger areas. If there is an embossed pattern in the old floor, you can use embossing fillers specifically made for the purpose, as deep embossing will read through the new floor in time. Then go ahead and lay the new floor. Just as a point of information for you and others, vinyl flooring and linoleum are two completely different products, and the terms cannot and should not be used interchangeably, especially when asking for or giving advice. They share no common ingredients, and differ as to underlayment requirements, adhesives, application methods, tools used, availability, lifespan, cleaning methods price,range of uses,... Anyway, not a big deal, just a "thing" with me. But anyone who really wants to be accurate ought to be aware.