Marking rows seems like a simple procedure - it almost seems like overkill, really.
Planting in rows makes your garden orderly and beautiful. It also helps you space your plants for optimal production; additionally, it helps you recover if seeds don't sprout, if a critter sheared off your seedlings, or if your starter plant bites the dust.
These things really happen!
Since you have your fence...
You've decided you might like to try gardening? That's great!
Have you considered gardening in a community garden? They're public spaces where people can rent or lease a small section of land (a "plot") and they can plant and tend a garden in the plot!
More on how a community garden works later... first you need to locate a community garden near you.
Many towns and cities have public community gardens. Yours probably does and you might not...