To describe them, you slipped your feet into the leather "toes" which were like shoes but open toed with laces to do up. Then you secured the skates by drawing a buckle around your ankles. It was like wearing sandles but they were made of metal and leather. If you wanted to make them longer, for bigger feet, you unscrewed the nut and bolt underneath and "stetched" them by unsliding a bit more metal until they were the right size. It's kind of hard to explain. Jacko was the name of the brand and it was printed in a slant across the leather toe bits.
No brakes! And solid rubber tyres. I was in my element and must have had them skates until I was about 16 at least!