I'm afraid I'm not familiar with PIC devices. But in principle, what you need to do, is:
1. Create hour, min and sec variables, and initialize to (say) 12, 0, 0 for 12.00pm
2. create an interrupt service routine that increments sec until it reaches 60, and then sets it to zero and increments min until it reaches 60, and so on.. At the end of the ISR, clear the interrupt.
3. Program the registers so that timer1 is set to cause an interrupt when it reaches a value that equals 1 second. For example if you were (say) using a 4MHz crystal, then the value will be high. Make sure you set any prescaler to any value so that the count fits in the PIC's counter register which will be 8 bits or 16bits probably
4. Now, in the main code function (assuming you're using C code - it really is not worth learning assembler apart from for very specific use-cases), just have a simple forever loop [i.e. while(1) ] that reads the
hour, min, sec variables and then outputs the corresponding codes to make your display do whatever you want. An 8x8 display is a bit odd for a clock. I'm guessing you want scrolling time. In that case, in an area of RAM (assuming you've got enough RAM), create a bitmap of the digits you want to display, and then have a loop that outputs them to the display, with (say) a delay of a few millisec as the multiplexing occurs. The code can repeat forever.
The above doesn't allow you to _set_ the time. For that, you need to adjust the code to incorporate switch inputs too - that could be a 'stage 2' feature once you've got the rest of it running.