Can't place tiles

Despite having a tile set and selecting a tile I can’t place any tiles. I can’t figure out the reason. Also I can’t put the tile set on the toolbar to the right, could anyone help?

Tiles you select in the Tileset Editor have nothing to do with what you’ve selected in the Map Editor, that’s probably why you can’t place them. To select tiles to use in the map, you need to select them in the Tilesets view in the Map Editor. Looks like you closed that panel, you can reopen it via Views > Views and Toolbars > Tilesets.