how to replace the slave cylinder on a 1999 nissan altima with the 4 cyl engine

I bought the car yesterday, so I am unsure at this time if there is any fluid loss going on. However, the master cylinder on the firewall was at the lower mark...the one that says ''minimum''. I have now filled it to the full level and can observe it to see if it goes down. At the minimum level, it should have had enough brake fluid in it to not be so low it would create a problem. I did not see any sign of fluid leak around the master cylinder ...or by the slave cylinder it self. When I first made this inquiry for advice, I was not sure where the slave was even located at. My worse fear was that it might have been in the bell housing....I have owned vehicles where it was located there...and it was a big job to replace them. Thankfully, I have now discovered that Nissan actually has their slave cylinder in an extremely easy place to get to it. The master cylinder, though, looks as if it would be rather hard to replace. I am a fairly capable and careful mechanic and can do it, though. I've never been employed as a mechanic, but have done most of my own car repairs over my 60 years. That said, I realize my experience is not up to par with those who earn their living as mechanics and always appreciate advice and help. I am just saying it still looks like I will have to be careful on the fluid line nuts. I have brake line wrench's, but even so...I will have to be careful. As I said ...I just bought the car yesterday and hardly know much about it. When I first sent this in for replies back....the clutch pedal was doing as I explained...that even though the pedal was all the way to the floor it was engaging the clutch ''immediately'' once you raised your foot instead of after the normal inch or so.''But today''...after it set all night...the hydraulic pressure has evidently gone back to normal again...and it is working fine again. Not sure why it would do that. I drove it three place today and it is still OK. Obviously I am worried about driving it someplace and getting stuck there because the pedal won't disengage the clutch. I know how to get a car home when that happens, but I hate to have to do that. I can even shift a manual without even using the clutch if I have to....but I hate to have to come to a complete stop...then I will have to start the car with it in gear. I live in Florida...so it is too flat here to try and park on a hill. Since i bought the car yesterday it does have a couple other issues I knew about....one of which is a broken motor mount that makes the engine raised up and down slightly if too much torque is put on the drive train while speeding up and slowing down...so staring the car with it in gear is not something I will want to do. So where does that leave me with needing help? Well...since it is now working normal again...I don't need any help. I can hope it was maybe just some air that worked itself out from the car sitting or something for whatever reason....I don't know the car's history...it was a ''cash car'' from a car lot. It's weird it was doing the problem one day, and the next day it was not. But my experience tells me this problem is going to return right away again. I am just not sure how to tell if it is the slave cylinder ...or the mater cylinder. Can you tell from this additional info I gave you? Luckily, the slave only cost's about $15...and the master only about $30. I may just replace both once I verify it is a problem that is going to return. It's a drag dealing with the initial problems of a new car sometimes...hoping there are no big surprises. this is a minor one. I only paid $600 for the car and it is pretty decent over all for that price. Everything works, including the AC, has good rubber, not wrecked, interior pretty nice. It had the motor mount issue I mentioned, and has 250,000 miles...and now this issue. I hope my $600 is not wasted. If there are no other issues that pop up and it last's a year...then it will beat driving my truck all the time and the 8 mpg it gets. Hope i did not over do it on the reply. Thanks for your attention.