First lets we look at the whole chapter:
Did We not expand for you, [O Muhammad], your breast?
And We removed from you your burden
Which had weighed upon your back
And raised high for you your repute.
For indeed, with hardship [will be] ease.
Indeed, with hardship [will be] ease.
So when you have finished [your duties], then stand up [for worship].
And to your Lord direct [your] longing. (Surat Ash-Sharĥ)
Now I am going to translate what it is written in the tafseer of Presidency of Religious Affairs of Turkey. (source, Turkish) I hope I can translate properly and also it helps.
The Prophet Mohammad(puh) and his companions were suffering the oppression and tortures of the polytheists in the time of Mecca. This situation was making both Mohammad(puh) and his companions sad. Then Allah revealed these verses in order to make them relieved and to herald them that there will be relief and success after these distress. According to hadith, when this chapter was revealed Mohammad(puh) said to his companions "Good news! The ease has come to you, 1 trouble can no longer win against 2 ease." (Muvatta’, “Cihâd”, 6; Taberî, XXX, 151).
There have been numerous comments about the verse 7 which is very brief and available to be interpreted differently (for example look Taberî, XXX, 152; Râzî, XXXII, 7). According to us, Ibn Âshûr's explanation "After finishing the one important job, tend towards an another important job, so that you may fill your all time with important jobs." which is not limiting the verse with any kind of special work or prayer seems accurate (XXX, 416-417). According to this interpretation, it is ordered to Mohammad(puh) and to all Muslims in the person of him that to put their time for good use and to give credit of both religious duties such as prayer, dua, tabligh etc and earthly duties such as working, producing, learning, teaching, helping etc.
In the last verse, it is said that a person should tend towards only to Allah for both work and prayer, do all of his/her work for the approval of Allah and wish from Allah whatever s/he wishes.
Also verse 7 is translated into Turkish with this meaning (again I am translating to English):
Then, when you finish one job, tend towards to another one.