How to activate turbo boost on i7 laptop?

Turbo boost is an automatic function, the CPU boosts the speed depending on things like load, heat, how many cores are in use, etc…
You can't force Turbo speeds…
You have a 2.6Ghz processor, that occasionally ramps up to 3.6Ghz when it is cool and there's an immediate demand for heavy load, then it drops back to regular speed. You don't. It only rises when it needs to for very short periods. The systems are not designed to run at the higher frequency. If you wanted a PC to overclock, you build your own tower with an appropriate CPU, motherboard, cooling system.

People mucking with their laptops damage them more often than improving them. The CPU will do it on its own if it needs to. If you have your battery setting on power saver it will never use it. If you have it on balanced it will do it when it needs to. If you have it on high performance it will always do it. Also, depending on the laptop, it may only be able to do it while plugged in. It is supposed to be automatic. Software might be preventing it while it isn't plugged in, since turbo mode uses much more power

You don't. It only rises when it needs to for very short periods. The systems are not designed to run at the higher frequency. If you wanted a PC to overclock, you build your own tower with an appropriate CPU, motherboard, cooling system.

People mucking with their laptops damage them more often than improving them.

The CPU will do it on its own if it needs to. If you have your battery setting on power saver it will never use it. If you have it on balanced it will do it when it needs to. If you have it on high performance it will always do it. Also, depending on the laptop, it may only be able to do it while plugged in.

It is supposed to be automatic. Software might be preventing it while it isn't plugged in, since turbo mode uses much more power