555 Questions on a new to me Machine

[HodgieMoggy]

Hi Group,
I recently purchased a 555 track loader while operating after about 15hrs I am getting the filter restriction light on. How do I go about clearing this light, what filter needs to be changed.
Second issue this loader used to have a hoe with it and recently acquired one for it how ever the piping for the hoe to the back of the machine had been removed, where do I plumb the lines from? I notice that there are two one inch ports on the main control spool however if these are the ports I don't know which is pressure and what is return. Any help would be appreciated.

Thanks,