Masts are typically one of two types. Either deck stepped or keel stepped.
Deck stepped masts stop at the deck and are held up by the shrouds (port and starboard), forestay and backstay. To lower this type of mast you can start by having someone support the mast, loosen the port and starboard shrouds (you typically do this at the turnbuckles) also note, you do not have to disconnect theses yet. Remove the bolt if present at the mast deck mount, disconnect any mast wiring (lights, vhf, etc.) if possible and then disconnect the forestay. Now while slowly walking the forestay back have the person supporting the mast slowly walk the mast down. On your boat two people can do this pretty easily. Larger boats will require a gin pole or crane.
For a keel stepped mast, you will need to disconnect all of the shrouds, forestay and backstay along with any wiring and then loft the mast out of the boat. This will be easier with a gin pole if one is available.
If there are other sailors around who have boats, ask them for some assistance. They will be there in person and can give you direct assistance.
Have fun with the new boat.