There are 3 recognized installation types, with variations on each.
NAILED DOWN: is the traditional method used for wooden floor installation. A nailed down floor is installed on timber battens, fixed to a concrete sub-floor. Solidwood Floors is using specialized nailing guns to fasten the battens to the concrete and the timber through the tongue to the batten. There is a cavity space between the floor and the concrete. Timber flooring does not allow for any moisture to rise from the concrete, so a moisture test needs to be done prior to installation. Make sure to use a moisture barrier, even if the floor is vented from the sides. A nailed down floor gives a traditional feel and can be noisier than other installation methods when you walk on it, but long, wide boards can be used.
GLUE DOWN: The timber is attached directly to a screed which would be sealed with a moisture barrier. The majority of floors now use this method with variations. Short lengths, end matched type of boards are mainly used for this application.
FLOATING FLOOR: is the fastest and easiest method of installation. Floating floors are not attached to any sub-floor, they simply float above it. Either adhesive is applied to the boards to keep them together, or the boards are made to simply snap together. Usually a pad is placed between the wood floor and the subfloor to protect against moisture and reduce noise. Floating floors can be installed over almost any surface. This method is not for solid wood floors, unless an Elastilon product is used. This is a cheap method but has limitations.