The market overview lets you quickly compare price movements on different timescales.
The overview shows three gauges, for the price movement during the last 60 minutes, 24 hours, and 5 days. Each gauge shows the current price in relation to the high-low range (with prices). A gauge which is mostly blue means that the current price is towards the top end of the range; orange means that the price is towards the lower end of the range. The inner bar then shows the open price for the period, and the corresponding % change.
Below the gauges are three simple candle charts, letting you compare short-term market activity on the M5, M15 and H1 timeframes.
The LTCUSD pair is the abbreviation of Litecoin against the US Dollar. Litecoin is another cryptocurrency like bitcoin. Some identify Litecoin as the silver to bitcoin's gold. The LTCUSD pair is a crypto/fiat pair as well. It is not an official currency pair, as LTC is not considered a "proper" currency for now, but it can be traded through various exchanges.