How my front door don't open from inside?

Sounds like the linkage between the handle and latch is either detached or broken (it is a mix of metal, cables and plastic bits). It is pretty straightforward to determine and you will have to start by taking the door panel off.

Trim tools are inexpensive and definitely help, but two things really help, a sunny day and warm plastic. Here is what I mean:

1) Do this on a hot sunny day! Yup, the weather is your friend when dealing with old plastic. Let the car sit in the sun with the windows closed and that plastic will be as plyable as it can be.

2) Remove the 2 screws hidden behind the door handle and in the armrest (they both have small "beauty panels" that hide the screws. iFixit's pry tool with the hook should help remove the panels).

3) Unplug the cable connectors for the speaker (pop off the small speaker panel first) and window controls (just a clip release and they slide out).

4) Grab the bottom center of the panel and give it a quick, short tug. If any of the clips are being difficult, pull out a bit and get a wide pry tool in next to it to give it some leverage. Once the panel is off the door, take a look at the backside to inspect the cable that runs from the handle to the latch. It may be detached or you may see damaged pieces (the plastic grommet at the end of the cable is suspect!). If you need a new door handle or cable, put the door panel back in place and get your replacement parts before going further.

When you do this, take your time! Those clips can be intimidating to pop out, but they will pop (given the age, they very well may break. Some panels have replacable clips, others have the clips molded into the panel).