Carlos , Welcome to APUG ! Here is the link for kodak retina IIa camera , manual is at the down of page , color or bw and 2 megabyte. You will need acrobat reader from adobe.com free.
Your camera and lens is at the top and better than all modern japanese cameras , especially than the digital ones.
For color , you can use Ektachrome as slide and Ektar as negative.
Tri X is matches with these cameras excellently. If you need chemical,film,tank etc , use APUG classifieds. Open an paypal account to yourself and trade with anywhere in the world