What is equivalent Resistor different Resistors put them in series or in parallel if they have a different wattage and different resistance?
Forget the wattage of the resistors to begin with, that's causing confusion. Do the analysis, combine resistors together first.

You can combine resistors in series or parallel. When in series the resistors add together. When in parallel, the calculation is a little more complex. Here are the two formulae you need.

When you combine resistance values together, the power doesn't come into it.

In practise, it's your job as a designer to ensure that you don't execeed the power rating for the resistor so you have to calculate the power dissipation of the resistor and ensure it doesn't exceed that stated for the resistor, so you need to work out the current through the resistor and what voltage is dropped across the resistor.  You need to know Ohms Law and Power formula (R=V/I , W =VI), re-arrange, combine if necessary and apply.

If you have a problem with actual power exceeding the maximum power rating for the resistor then there are things you can do to get around that: you can use multiple resistors in series, the current through each is the same but the voltage is shared across the resistors, thereby reducing the actual power dissipated by each resistor.

Alternatively putting resistors in parallel will reduce the current but keep the voltage the same.  But you have to ensure the the combined resistance of the multiple resistors (whether in series or parallel) achieves the value you want to achieve.