Automatic gearbox Lancia Y

Good afternoon, people! Whether someone can show me a tip or link or the like? The following problem: We have a Lancia Ypsilon 840 with petrol engine, 1240 ccm, 44 kW/60 hp, G-Kat first registration 28.2.97 automatic transmission The automatic transmission causes problems. If the gear lever is on N, the forward or reverse gear can only be switched on with a lot of force and patience when the engine is running. normal. I almost think that transmission oil is missing, because the transmission is externally oily and lubricated. It has already been refilled in a workshop once oil and then the car went better. Can anyone of you tell me where the Östand is controlled, how much oil has to be refilled or changed, which change interval and above all what is the right oil type. Does anyone know this error. I would be very grateful for (numerous) tips, because the workshop already wants the transmission we Many greetings from Robert