Have you spoken to the County Clerk? They can be helpful in deciding how to start. I don't know what County you're in, but Hillsborough County says this about filing;

Complete the “Unlawful Detainer Complaint” and the “Unlawful Detainer Summons” forms. You are the Plaintiff and the person you want removed from your property is the Defendant. You will be given a Case Number and Division when you file the case with the County Clerk’s office. All completed forms are filed with the Clerk’s office, County Civil Division, 1st Floor, Room 103, George E. Edgecomb Courthouse, 800 East Twiggs Street, Tampa, FL 33602.
STEP 2 - Notary
Sign the “Unlawful Detainer Complaint” in front of a notary. The clerk’s office will notarize documents for a fee.
STEP 3 -Make copies
Make at least 2 copies of the completed Complaint and Summons (1 copy for you and 1 copy to be delivered to the Defendant). Copies can be obtained for a fee in the Court Business Center, on the 6th floor of the George Edgecomb Courthouse.
STEP 4 - Filing your case
Take the original Complaint and Summons to the County Clerk’s office. The Clerk will charge a filing fee. The Clerk will issue the Summons and give it back to you.
STEP 5 - Notifying the other party (Defendant)
The Summons must be served by either the Sheriff or a Certified Process Server. Take the Summons and one copy of the complaint to the Sheriff’s office and pay the fee to have the Defendant served. Hillsborough County Sheriff’s Civil Process is located at 700 Twiggs Street on the 3rd floor (across the street from the main courthouse). A non-refundable fee is required (only cash, cashier’s checks or money orders -- no personal checks).
STEP 6 - After the Defendant is served
After the Summons is served to the Defendant, the Defendant has five (5) working days to file a response regarding the case. (Do not count the day of service, Saturdays, Sundays or observed legal holidays.) After 5 working days have passed, the paperwork to complete the case may be filed.
If the Defendant filed an answer, file a request for a hearing in the Clerk’s office. There is no form for this. You may use a plain piece of paper to write your request. Make sure you include the case number and the names of the parties. You will be notified by mail when the hearing is scheduled.
If the Defendant did not file an answer, and is not in the military, complete the following forms and take them to the County Clerk’s office. (If the Defendant did not file an answer and is in the military, STOP HERE and consult an attorney.)
a. Motion for Default & Default
b. Non-Military Affidavit (must be notarized)
c. Judgment for Possession (complete the heading only - names and case number)
d. Writ of Possession (complete the heading only - names and case number)
The Clerk will file your documents and take the Judgment for Possession to the Judge to be signed. Once the Judgment for Possession is signed by the Judge, the Clerk can issue the Writ of Possession. The Sheriff’s office charges a fee to execute the Writ of Possession and remove the Defendant.
STEP BY STEP INSTRUCTIONS
2013-03