Jak mogę dostać się na ...? 'How do I get to ...' is the example in the phrases. It is useful for various reasons, but is not the easiest way to ask for directions (see below).
The simplest way to ask how to get somewhere is Gdzie jest...? 'Where is ..?' followed by the location (in the appropriate case).
In these examples, following Gdzie jest...?, the Nominative Case is used. This is straight-forward, as words are listed in dictionaries in the Nominative.
If you want to learn more Polish for free, there are 500 Polish sentences covering conversational situations.
A few first words. 1, A few first words. 2, A few first words. 3, Bathroom. Items, Bedroom. Items, Buying things. General phrases, Buyings things. Useful words, Countries, Communication problems, Conversation. Introductions, Conversation. Small talk. 1, Conversation. Small talk. 2, Conversation. Filler words, Conversation. Small talk. Sport, Conversation. Small talk. The weather, Days. General, Days of the week, Describing things. Colours, Describing things. Adjectives, Asking for Directions, Understanding Directions, Eating items, Eating phrases. 1, Eating phrases. 2, Emergencies, Family, Food and drink. General phrases, Food and drink. At the bar or café. 1, Food and drink. At the bar or café. 2, Food and drink. At the bar or café. 3, General phrases, Getting around. General phrases, Getting around. Train and bus, Getting around by taxi, Getting around by car, Health, Household items, Money, Months of the year, Numbers. 1 to 10, Numbers. 11 to 20, Numbers. 30 to 1000, Parts of the body, Places and buildings. 1, Places and buildings. 2, Question and size words, Somewhere to stay. 1, Somewhere to stay. 2, The house, Useful words to recognize, Words to do with food. General, Words to do with food. Fruit, Words to do with food. Meat.