To reach mukti, the person must be gurmukh. This is a person centres themselves around God, following the ways and teachings of the Guru’s, and not temptations or desires. A Sikh must understand, experience, and put their focus and attention on God. God cannot be entirely understood by humans but however can be experienced through means such as love and worship. Therefore, regardless of where it takes place, prayer can lead you to mukti. Reaching mukti also means you are gurmukh as you are following God’s and the Guru’s ways, and because being gurmukh is the only way to be liberated from samsara.
Sikhs only worship God whom is seen to have no fixed description; prayer is considered as a way of spending time in the company of God. At a Gurdwara all members of the congregation sit cross-legged on the floor as a sign of equality while the ardas and the reading of the Guru Granth Sahib is carried out by the Granthi, and also during kirtan. This is known as public worship.
Congregational/public worship takes place in a Gurdwara and it is important as Sikhs believe it brings them closer to God. Sikhs consider congregational worship/sadh sangat to be special. They believe that God is visible within the sangat and that the act of serving the congregation pleases God.
However, Sikhs can and are expected to partake in private worship. Prayer is not confined to the Gurdwara and it can happen at any time and any place. Sikhs have set prayers to recite in the morning, evening and before going to sleep, and there is also a strict way to start each day. They must wake up three hours before dawn, bathe and meditate/concentrate their thoughts on God.
The daily prayers that Sikhs are expected to read are; Nitnem which consists of reading Japji of Guru Nanak, Jap (repetition of name of God) and Ten Swayyas of (group of hymns by) Guru Gobind Singh in the morning. Rahiras which is a collection of nine hymns by Guru Nanak, Guru Amar Das and Guru Arjun to be read in the evening at sunset. And Kirtan Sohila which consists of five hymns by the same three Gurus to be read before going to sleep.
Sikhs believe in both private and public worship. Neither makes you a better Sikh, though private worship is expected more so than public. Going to a Gurdwara to worship in a congregation is seen to have spiritual benefits, but private prayer in the home is the foundation of Sikh worship. I believe that as long as the required hymns and prayers are recited daily with complete devotion to God, and a person lives their life in a gurmukh manner, then you do not have to go to a Gurdwara to be a good Sikh.