With many of the sony tvs you press menu, then use the cursor to navigate down to the bottom icon, press enter, OK or the right hand cursor, (can't remember if you get a choice for auto or manual), if you go to manual, navigate down to the programme number you want to tune and use the cursor to cross over to the frequency/channel column, you can then either enter the real channel number or use the up or down to scan.
Alternatively, describe the remote and give a list of the rows of buttons, it may help to identify the tuning method.