Promesa

Located on the tenth level if you're going by Scene Selection, otherwise this is the level where you have to go down many flights of stairs. Begin by going all the way down the stairs to the bottom. From here, take a sharp right and go outside. If you look up and to the right you'll see some shirts hanging on a balcony, look at the red one until the La Camiseta achievement pops. From here walk to your left and past the red scooter, taking another left down the alley. Walk through here to get warped to the kitchen area and then walk inside. If you look to your immediate left on the counter you'll see a grey cup with a straw to the right of a microwave, look at it until the Mate achievement pops.

I recommend finishing the level after this instead of quitting out, when I quit out the Scene Selection option vanished and I had to force quit the game to make it reappear. To end the scene just look at the golden bicycle at the far end of the kitchen.

The Jersey and the Mate can be found on the 10th level using stage select (Thumbnail is inside of an apartment building with a window and staircase) walk outside of the building to the right and look up and you should see some a jersey and some clothes hanging on a drying line, walk close and the achievement should unlock.

I show the location in my Achievement Walkthrough starting at 2:41 in the video.

After beating the game you unlock stage select.
On the 10th stage there's a jersey you need to look at for an achievement

See in video at 6:10
Achievement Walkthrough: