ACS assessment for UK Contractors

Hi There,
i am British citizen and past 10 yrs i have been working as contractor through my Ltd company (director) . i have been working on various length of contracts but renewed every 6 months through my ltd company and i get paid in to my business account. i have to complete RTL as i am from non it back ground. can you please let me know what are evidence i need to provide to ACS for assessment? do i have to provide my contract signed through my ltd company? or how should i proceed with documentation? is anyone been in the similar situation?
your quick help will be appreciate

Regards