If you are not comfortable cooking tofu please try this INCREDIBLY SIMPLE RECIPE.
Using ponzu sauce (Japanese soy sauce that contains Yuzu) is the best, but it is expensive and you might have difficulties finding it.
The recipe below is a cheap and easy alternative.
(the enclosed photo is with konjac noodles topped with seaweed flakes)
Press the block of tofu to get rid of a maximum of water. Cut it into rectangles (approx 1cm x 2cm), 0.5cm thick.
Mix the lemon juice and the soy sauce and marinate the tofu pieces for as long as possible (it gets tastier if left overnight, but will still be nice if left to stand for 15 minutes)
In a pan, heat the olive oil and add the tofu pieces without the marinade. When the first side gets crispy, turn the pieces on the other side. When fully crispy, bring down to medium heat and cook for 5mn.
Add the marinade to the pan and cook for another 5mn or until it is evaporated.