In each cell you are shown on the initial letter of the country inside it. Each country touches either horizontally or vertically a country it borders on the world map.
Notes:
1) Grey cells are left empty 2) A country in the bottom row can also 'touch' the one in the top row that is in the same column 3) Only one country name consists of more than 2 words 4) Countries in C and G do not border 5) Dubious Qatar-UAE border is considered