How we cite our quotes:
Often the lone-dweller waits for favor,
mercy of the Measurer, though he unhappy
across the seaways long time must
stir with his hands the rime-cold sea,
We learn here that the person in question travels "unhappy," implying that he doesn't want to travel, but is forced to for some reason. Also, he's called a "lone-dweller." An Anglo-Saxon would be unlikely to travel alone unless he was separated from his kinsmen by circumstances beyond his control. Both of these descriptions of the person point to his status as an exile, someone forced to travel away from his friends and family. The fact that he treads "exile-tracks" confirms our assumption. This last description of the speaker conveys that the way of the exile is a well-established one: the person follows in the footsteps of others, sharing the same experience they have had.
So must I my heart –
often wretched with cares, deprived of homeland,
fasten with fetters.
If there was any doubt in our minds about whether our speaker's an exile, these lines remove it. He calls himself "deprived of homeland," so we know that he's been forced to leave it for some reason. The fact that he's also "wretched with cares" suggests that he left for reasons beyond his control.
[…] Long ago earth covered
my lord in darkness, and I, wretched,
mad and desolate as winter,
over the wave's binding sought, hall-dreary,
a giver of treasure, where far or near
I might find one.
The speaker explains the reason for his aimless wandering and suggests a reason for his exile. He has buried his lord and now looks for another one. A lord was an absolute necessity for an Anglo-Saxon warrior, the source of protection and wealth, and the mead-hall where the warrior found shelter. The speaker calls himself "hall-dreary," by which he probably means he's sad because he doesn't have a hall anymore.