The website has the following elements:

It has 3 different frames, how do I navigate myself to the
You can actually select an iFrame using the below methods: -
frame(Name of Frame [or] Id of the frame)
frame(WebElement frameElement)
So you can switch by passing the any above information about the frame. Yes you need to switch everytime according to require action
As we can see your frame have different name like :- top, navigation etc. Use name of the frame to switch between them
Example:-
driver.SwitchTo().Frame("top");
.... Perform your action on frame
driver.SwitchTo().defaultContent();
driver.SwitchTo().Frame("navigation");
.... Perform your action on frame
driver.SwitchTo().defaultContent();
Hope it will help you :)