How to install round brake pads I decided to change my bike's brake pads myself. My bike has the following brakes: Promax DSK-915. I contacted the online shop I ordered my new brake pads (and my bike last year), before purchasing, and they told me that these are suitable for my bike: Cox DBP-06.87-R Disc Brake Pads.

I got them today, but I have no idea how to put them on my bike, as the old ones I have are not rounded and have little hole that's used to put them in place.

Below you can see my old brakes. The "thing" (split pin/cotter pin) I circled in red goes in the little holes I marked with numbers. 



I don't understand how I can install my new ones on my brakes:



Is that even possible? Or the online shop suggested I buy the wrong product? I am so confused.
You got the wrong pads.

While it's possible to mix and match some pads, this is usually not the case. When replacing pads, keep track of:


Pad material and what your rotor is compatible of. Some rotors have a "resin pads only" etched on. Consult user manual or manufacturer website for this info.
Pad shape. Note the features, like "handles" shape, amount and location of holes and protrusions.


The pad you want has is called DBP-01.23R. It's a Shimano-compatible (B01S analogue), very wide spread model, you should be able to source a pair from any half-decent bike shop. The round pads are for Promax Render and Decipher and won't work with your Solve.