OK; I can see that you've been a Ham for less than 6 months. It would help you immensely if you found a local Ham radio club. In the mean time, be careful with operating the radio lest you break it out of not knowing any better at this point. Not to worry; we all go thru this if we don't have an instructor standing over us.
Trying to understand the operating manual w/o having a practical knowledge of the terms used is confusing - to say the least.
First of all, you are going to have to find the nearest repeater close to you. This info can be had on the internet. Or, if you know what they are already - look up their website to find the repeater info; should be somewhere on that page. You will need to find out the listening freq first (such as 145.230mHz or whatever). Then you should also see a "+" or a "-" associated with that number; this is the freq offset. A repeater will have a separate listening freq and a transmitting freq; the offset "+" or "-" will send either a transmit freq when the mic is keyed depending on which way it is set. Let's say that it is "-" for he freq I gave. Which is the typical offset for that freq - BTW. The radio - when keyed - will transmit 600kHz BELOW that listening freq.
Now we have gotten past the offset part. We now need to look on that repeater page and find the 'PL Tone'. The PL Tone is a sub-audible frequency burst that will happen when you key the mic. It acts like a 'key' to unlock the repeater and lets it know that there is an incoming freq to the repeater transmitter. This tone is a number that is somewhere between ~86hz to upwards of ~250hz; every repeater has this set at a different freq - so we have to be specific.
I use a Yaesu FT-8800R; so it should be the same as your 8900 - or very close to it.
To access the adjustments of these controls, your Yaesu radio will have a button in the center/lower part of the panel - just below the display. Pushing it once will cause one side of the radio to change the display on whichever (left or right) side of the radio you are on. First turn either the upper left or right knob to so that you can scroll thru the menu items. Find the item that says: 'HYPER'. Now, press the same knob once again and that you were scrolling with - and scroll it again until you find "AUTO' (it will say 'AUTO' or 'MANUAL'). Set it on 'AUTO' and press that knob again; you have just set the auto repeater offsets. Next scroll that kno until you find the 'TONE F' and then press that knob again. Numbers will appear that look like '100.0HZ'. If you turn that knob now, the numbers will increase or decrease. Find the number of the PL Tone for the repeater and then push that button to set it to your needed PL Tone. Once you have set the PL Tone; turn that same knob until it says 'TONE M'. Press that same knob and scroll until it says 'ENC.DEC'. Then press that knob. You are done!
