I have two CSV files. Their content looks like:

3,7578.8374
4,4911.78
5,4922.014
6,3158.1414
7,2656.271
8,2520.162
9,1659.447
10,2295.329
...

The simplest way to load and draw them is by using pandas and matplotlib.

import matplotlib.pyplot as plt
import pandas as pd
one = pd.read_csv('./my1.csv', names = ['step', 'loss'])
two = pd.read_csv('./my2.csv', names = ['step', 'loss'])
plt.plot(one['step'], one['loss'], label = 'my1')
plt.plot(two['step'], two['loss'], label = 'my2')
plt.ylabel("Loss")
plt.xlabel("Training step")
plt.legend(prop = {'size': 10})      # Set size of legend to be smaller
plt.show()

The figure draw out by this snippet is shown below: