First off, I think there are many on here who bought their turtles without having done any research, I was one of them. I also bought them on impulse getting 3 at one time. There are also others who have had their turtles for years and have been doing many things wrong. Now that being said. I'm glad you're taking the time to do research now instead of waiting down the line and doing harm to your turtles..
It's best for you to read the forum, search for information on specific questions you have, also read the main website... that is packed with valuable information regarding just about anything you could want to know about RES. If you can't find an answer to a specific question, someone will try to help you or direct you to where you can find the proper answer.
You have a significant amount of questions which can easily be found either on the forum or the website, so I suggest you start by doing some reading
I will answer two of your questions which if not answered soon, could cause health problems for your turtles.
how long should i keep them next to the window?You should NEVER put them next to a window. They will get no benefit from the sunlight other than perhaps some heat, which should be taken care of with a fully submersible water heater. Leaving them next to a window could cause the water to overheat and kill the turtles. Also it will cause algae to grow in the tank.
when should i move them out of the plastic container i got them in and what should i put them in?You should move them out of that NOW. That container is what we call a "death bowl" It is not suitable for anything. You should put them in a container what will allow for at least 10gallons of space per inch of shell (excluding the curve). It can be either a glass aquarium or a plastic (rubbermaid or sterlite) container. Again, please do some reading regarding the proper habitat for your new pets.
You are ultimately responsible for their health and wellbeing. May I ask your age and where you live? Just curiousity here
